Controller and method for controlling a capacitive touch screen or the like

• US 9,870,103 B2
• Filed: 01/03/2012
• Issued: 01/16/2018
• Est. Priority Date: 01/03/2012
• Status: Expired due to Fees

• Current Assignee: Silicon Laboratories Incorporated
• Original Assignee: Silicon Laboratories Incorporated
• Inventors: Konradi, Vadim, Dorris, Parker, Franklin, Michael, Welland, David R.
• Primary Examiner(s): Patel, Kumar
• Assistant Examiner(s): ONYEKABA, AMY
• Application Number:
  US13/342,658
• Publication Number:
  US 20130169583A1
• Time in Patent Office: 2,205 Days
• Field of Search: 345173-174
• CPC Class Codes: G06F 3/04166 Details of scanning methods, e.g. sampling time, grouping of sub areas or time sharing with display driving Synchronisation with the driving of the display or the backlighting unit to avoid interferences generated internally G06F3/04184
• CPC Class Codes: G06F 3/04182 Filtering of noise external to the device and not generated by digitiser components
• CPC Class Codes: G06F 3/0445 using two or more layers of sensing electrodes, e.g. using two layers of electrodes separated by a dielectric layer
• CPC Class Codes: G06F 3/0446 using a grid-like structure of electrodes in at least two directions, e.g. using row and column electrodes

Abstract

A controller for a capacitive touch screen or the like includes a touch resolve subsystem and a processor. The touch resolve subsystem, when activated, measures a plurality of capacitance values using a plurality of input pins. The processor uses the plurality of capacitance values at each of a plurality of values of a parameter to create an interference map.

Claims

1. A controller for a capacitive touch screen, comprising:

a touch resolve subsystem that, when activated, measures a plurality of capacitance values using a plurality of input pins; and

a processor that uses said plurality of capacitance values at each of a plurality of values of a parameter to create an interference map, said interference map identifying a level of interference at each of said plurality of values of said parameter, and said values vary over an allowed range, and to select a desired value of said parameter based on said interference map over said allowed range, wherein said parameter comprises a desired scan frequency,

wherein said processor uses said interference map to select said desired scan frequency based on both said level of interference and scan frequency for each of a plurality of scan frequencies.

2. The controller of claim 1, wherein said processor selects a first scan frequency instead of a second, lower scan frequency when interferences at said first and second scan frequencies are approximately equal.

3. A controller for a capacitive touch screen, comprising:

a touch resolve subsystem that, when activated, measures a plurality of capacitance values using a plurality of input pins; and

a processor that uses said plurality of capacitance values at each of a plurality of values of a parameter to create an interference map, said interference map identifying a level of interference at each of said plurality of values of said parameter, and said values vary over an allowed range, and to select a desired value of said parameter based on said interference map over said allowed range,

wherein said parameter comprises a number of scan pulses per scan line.

4. A controller for a capacitive touch screen, comprising:

a touch resolve subsystem that, when activated, measures a plurality of capacitance values using a plurality of input pins; and

a processor that uses said plurality of capacitance values at each of a plurality of values of a parameter to create an interference map, said interference map identifying a level of interference at each of said plurality of values of said parameter, and said values vary over an allowed range, and to select a desired value of said parameter based on said interference map over said allowed range,

wherein said parameter indicates whether to implement a highpass filter in said touch resolve subsystem.